Abstract: A system for printing background and foreground colors in response to mask data and printing instructions. Page description language data is separated onto three lines, two for Contone and solid colors, and one for control (mask data and instructions). The mask and instruction data is transformed into a series of multi-bit command words, each describing a pixel in terms of 1) control tag bits to specify color, 2) object optimized rendering tag bits to describe the type of color (solid, text, sampled or line art), 3) color space transformation bits to control conversion from other spaces to CYMK and 4) format tags to specify the number of bits per pixel. This series of command words combines information on one line that required at least two lines in the prior art, and the data is in easily compressable form, resulting in simplified hardware.

Abstract: This is a circuit and method for adaptively selecting one of a plurality of predictor patterns to encode a stream of image data blocks such as would be output from a raster-input-scanner. A variety of halftone and nonhalftone predictor patterns are used and compared, with the best one being selected to predict the next block. Using this technique, the best predictor pattern is usually selected, predicted data buffering is not needed, and no code need be transmitted with the data to the receiver to specify the predictor to be used in the deprediction process since the same basic information is also available to the receiver.